Method for cutting bone or cartilage with a rongeur

ABSTRACT

An improved multi-bite bone cutting rongeur with an ultrathin foot plate and a disposable cutting element and storage chamber unit is disclosed. The present invention has an integrated cutting element and storage chamber unit that is truly disposable, rather than merely replaceable. The present invention requires the use of no tools or special assembly. The chamber is simply placed onto the shaft whereby it is immediately locked into place by the use of the instrument.

This application is a divisional of application Ser. No. 10/765,341,filed Jan. 27, 2004; which is a continuation of application Ser. No.09/790,008, filed Feb. 21, 2001, now U.S. Pat. No. 6,695,849; which is acontinuation of application Ser. No. 08/108,908, filed Aug. 18, 1993,now U.S. Pat. No. 6,200,320; which is a continuation-in-part ofapplication Ser. No. 07/905,127, filed Jun. 24, 1992, now abandoned;which is a continuation of application Ser. No. 07/398,987, filed Aug.28, 1989, now abandoned; all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical instruments, and more particularly tosurgical instruments used to bite out or cut portions of bone orcartilage.

2. Description of the Related Art

Rongeurs are surgical instruments for the cutting away of human tissue,and most commonly, cartilage and/or bone. At present there is a need fora rongeur having a less cumbersome and less intrusive foot plate whichwould make the instrument safer for use in the spinal canal and aboutthe delicate neural structures and extend the range of use of theinstrument by allowing it to be used in closer proximity to those samestructures.

Attempts have been made in the past to provide a rongeur with a lesscumbersome foot plate. For example, U.S. Pat. No. 4,990,148 issued toWorrick, Ill. et al. (“Worrick”) on Feb. 5, 1991 teaches a means forallowing a limited reduction of the foot plate thickness by the additionof a groove placed at the junction of the foot plate to the shaft forthe purpose of relieving crossed fields of stress. However, the footplate of Worrick is still internally cupped to maintain a cutting edge,which thus limits any further reduction in the thickness of the footplate.

Essentially flat foot plates had been in use earlier this century, butproved to be undesirable because spinal bone is markedly compressedduring the biting process. When the foot plate is flat, the mass of bonebitten is forcefully compacted into the singularly cupped recess of themovable jaw such that it is extremely difficult to remove that boneafter each bite.

At present, there is also a need for a rongeur with a capacity to remainwithin the wound and to repeatedly bite and to store the bone bittenuntil all the requisite bone removal has been completed without the needto continuously remove the rongeur from the wound for the purpose ofremoving the bone from the instrument to clear the cutting edges. Afurther and related need is for a rongeur that would collect and containall of the bitten material such that the delicate neural structureswould be protected from contact with the bitten material and/or anycogenerated inadvertent debris. In this regard, any rongeur can bitemore than once, but not properly. That is, one could deliberately takeseveral small bites, each of which would fail to fill the cup in thefoot plate and the singularly cupped recess of the moveable jaw, in lieuof taking one full bite. However, once the cup and the cupped recess arefilled further biting is not possible. Bone may be crushed as cups thatare already full approach one another, but their contents will shieldany further interposed bone from the cutting edges, thus making anyfurther bone cutting impossible.

An example of a multibite rongeur is shown in U.S. Pat. No. 3,902,498issued to Niederer on Sep. 2, 1975. Niederer teaches the use of arongeur hollow at the tip such that it is possible to take severalbites. Unfortunately, since the hollow tip is open to the wound at bothends, the further use of the instrument pushes the already bittenmaterial out of the other end of the hollow tip and back into the depthsof the surgical wound where it can cause great harm.

Finally, there is also a need for a surgical rongeur that will upon eachuse present a perfectly formed and razor sharp cutting edge, which willmate exactly, and close completely, to the opposed foot plate. In thisregard, Niederer taught the use of a disposable cutting element but notthe use of a disposable storage chamber for the cut pieces.

Of note is U.S. Pat. No. 5,026,375 issued to Linovitz et al. on Jun. 25,1991 which claims a modification of Niederer's teaching wherein the tipis replaceable rather than disposable, in that it requires assembly andis secured with a screw, and wherein the tip has extending from itslower surface an inverted “T” shaped portion made to be inserted intoand engage with a correspondingly internally disposed inverted “T” slotwithin a portion of the instrument shaft.

A further problem with the design of conventional rongeurs limitingfurther thinning of the foot plate so as to maintain adequate strengthis that since the opening of a conventional rongeur is much greater inits capacity than the sum volume of its cuts, in the process of bitingwith such a rongeur, the bone is not only bitten but is furthercompacted under tremendous pressure, that pressure being transmitteddirectly to the foot plate.

Conventional rongeurs by design have excursions beyond that needed tomerely close the jaw completely when the rongeur is new. That is becausethe manufacturer must allow for the wear that will occur at the cuttingedges, and yet still provide for the capacity of the instrument to stillclose fully later. Thus, when bone is bitten with a conventionalrongeur, a force considerably greater than that necessary to cut or evencompact the bone is additionally transmitted to the foot plate as theslidable member attempts further proximal migration in opposition to thefoot plate.

SUMMARY OF THE INVENTION

The present invention is an ultra-thin foot plate, multi-bite rongeurwith an integral storage chamber and cutting element that is replaceableand disposable. The integral storage chamber and cutting element of thepresent invention is removably locked to a central shaft and isremovably engaged to a driving member. The integral storage chamber andcutting element slides along the shaft towards a foot plate at thedistal end of the shaft in response to the movement of the drivingmember which may be hand operated or powered by a solenoid or apneumatic means.

The ultra-thin foot plate of the present invention is made possible bythe complete absence of a cup. The foot plate shaft junction area of thepresent invention is designed to mitigate the stress concentration ofthe junction. The foot plate of the present invention need not be asthick as that of a conventional rongeur since the only force applied toit is that sufficient to actually cut the bone being bitten. During use,the integral storage chamber and cutting element is closed at itsproximal end and open at its distal end terminating in an ultra-sharpcutting surface. The interior cross sectional area of the storagechamber flares in both height and width from distal to proximal.Inasmuch as the cutting element storage chamber unit is hollow, ratherthan cupped, and the opposed surface of the foot plate is flat, the bonebitten is always driven rearward into the chamber portion. As thestorage chamber is closed while in use except for the cutting entrance,it may be used to repeatedly bite bone without the danger of the bonebitten coming free and falling into the spinal canal.

When the present invention has completed its task and removed all of thebone as needed, the integral storage chamber and cutting element may beremoved from the shaft of the rongeur and the bitten bone may be removedfrom the storage chamber and made available for use, as in performing aspinal fusion.

The present invention allows for the clean cutting of bone or cartilagewithout any compaction. Further, as the cutting element of the presentinvention is disposable and thus always fresh and sharp, less force isrequired during the actual cutting of the bone. In addition, since theintegrated cutting element storage chamber unit is always fresh andsharp, edge wear is not a problem and the capacity for further excursionof the cutting element towards the foot plate is unnecessary and may becompletely blocked, thereby sparing damage to the foot plate.

Finally, the present invention has an integrated cutting element andstorage chamber unit that is truly disposable, rather than merelyreplaceable and requires no special assembly or the use of any tools.The integrated cutting element and storage chamber is simply placed ontothe shaft whereby it is immediately locked into place by the use of theinstrument itself.

OBJECTS OF THE PRESENT INVENTION

It is an object of the present invention to provide an improved surgicalrongeur capable of making multiple bites or cuts of bone or cartilagewithout being removed from the wound after each bite or cut.

It is another object of the present invention to provide an improvedsurgical rongeur capable of storing multiple cut pieces of bone orcartilage while the rongeur is in the wound.

It is yet another object of the present invention to provide an improvedsurgical rongeur having an integrated cutting element and storagechamber.

It is a further object of the present invention to provide an improvedsurgical rongeur having an integrated cutting element and storagechamber unit that is easily replaceable and disposable.

It is yet a further object of the present invention to provide animproved surgical rongeur having a replaceable and disposable integratedcutting element and storage chamber unit that does not require the useof tools or special assembly.

It is still a further object of the present invention to provide animproved surgical rongeur having an integrated cutting element andstorage chamber unit where the integrated cutting element and storagechamber is simply placed onto the shaft whereby it is immediately lockedinto place by the use of the instrument.

It is another object of the present invention to provide an improvedsurgical rongeur with an ultra-thin foot plate that is flat.

It is yet another object of the present invention to provide an improvedsurgical rongeur that allows for the clean cutting of bone or cartilagewithout any complication.

These and other objects of the present invention shall be more clearupon review of the following detailed description of the drawings whenreviewed in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective side view of an improved bone rongeurconstructed in accordance with the present invention.

FIG. 2 is an exploded first side view of an improved bone rongeurconstructed in accordance with the present invention.

FIG. 3 is an exploded second side view of an improved bone rongeurconstructed in accordance with the present invention.

FIG. 4 is a bottom plan view of the slide drive member engaged to thecutting/storage member and a side view of the body of the surgicalrongeur of the present invention.

FIG. 5 is a top plan view along lines 5-5 of FIG. 4 of the shaft portionof the rongeur of the present invention showing the configuration of theslot and recess.

FIG. 6 is a cross sectional view along lines 6-6 of FIG. 1.

FIG. 7 is a partial schematic view of the spring means for biasing thehandle of the rongeur of the present invention.

FIG. 8 is a perspective view of an alternative embodiment of thecutting/storage member of the present invention including a disposablestorage and cutting element.

FIGS. 9A and 9B are perspective views of further alternative embodimentsof the cutting/storage member of the present invention including adisposable storage and cutting element secured to the bottom portion ofa carrier member.

FIGS. 10A and 10B show a partial schematic side view of anotheralternative embodiments of the foot plate and the cutting/storage memberof the present invention.

FIG. 11 is a perspective side view of an alternative embodiment of thepresent invention showing a power rongeur.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1-4, the improved surgical bone rongeur 10 is shownconstructed in accordance with the present invention and consistsgenerally of a body 12 having a rear handle 13 depending at an anglefrom the proximal end 11 of the body 12, and has a shaft 14 extendingdistally and terminating at its distal end in a foot plate 16. A supportspike 31 extends from the upper portion of the rear handle 13 as supportfor the area of the hand between the thumb and the first finger. Mountedon the shaft 14 is a slide drive member 20 for reciprocating movement onthe shaft 14. The slide drive member 20 has a pin 42 located at itsbottom surface near its proximal end as shown in FIG. 4.

Referring to FIG. 2, a pivoting forward handle 30 includes a lowerfinger grip portion 34 and an upper finger portion 37 for the fingers.The upper part of the forward handle 30 has an extension 33 with anelongated opening 35 and an aperture 36 through which passes a pivot pin32. Extension 33 fits into the body 12 through slot 19 (shown in FIG. 5)and is contained within the body 12.

Once the extension 33 is positioned within slot 19, the pivot pin 32,having a screw head 39 on one end and threads at its other end, is usedto pivotally attach the forward handle 30 to the body 12. The pivot pin32 passes through opening 15 in one side of the body 12 through aperture36 in the forward handle 30 and threads into threaded aperture 17 in theother side of the body 12. The elongated opening 35 of the extension 33surrounds the pin 42 of slide drive member 20 mounted on the shaft 14 sothat the forward handle 30 engages the pin 42 and serves as the drivingmeans for the slide drive member 20. The forward handle 30 is attachedto the body 12 at an angle to the slide drive member 20 so that when theforward handle 30 moves proximally the slide drive member 20 movesdistally.

The forward handle 30 and the rear handle 13 are biased away from eachother by spring means 40 and 40 a. Spring means 40 is attached at oneend to the bottom of forward handle 30 by screw 41 and spring means 40 ahas one end attached to the bottom of rear handle 13 by screw 43. Inorder to interlock the two spring means 40 and 40 a, spring means 40 hasan extension piece 45 at its upper end that fits into the notch 46 ofthe upper end of spring means 40 a as shown in FIG. 7. Once interlocked,the spring means 40 and 40 a oppose each other to bias the forwardhandle 30 distally. Other spring mechanisms, internal or external, andother biasing means, including pneumatic means, may also be employed forurging the forward handle 30 distally.

Referring to FIGS. 4 and 5, the slide drive member 20 is slidablymounted to the top surface of shaft 14 within a slot 24 formed in theshaft 14 having an inverted T-shaped portion 25 into which is fitted acomplementary inverted T-shaped runner 26 depending from the bottomsurface of slide drive member 20. Slot 24 extends distally from theinverted T-shaped portion 25 to form a wider portion 27 of the slot 24.

Referring to FIG. 4, a stop pin 60 depends from the distal end 61 of thebottom surface of the slide drive member 20. The stop pin 60 serves toguide the slide drive member 20 to keep the distal end 61 of the slidedrive member 20 from sliding off the shaft 14 during the operation ofthe rongeur 10. The stop pin 60 is set back from the distal end 61 ofthe slide drive member 20 and fits within the wider portion 27 of slot24. The wider portion 27 of the slot 24 has a slot wall 28 at its distalend which catches the stop pin 60 and prevents the slide drive member 20from sliding off the shaft 14 distally.

Referring back to FIG. 2, on one side of the shaft 14 is a roundedaperture 80. The rounded aperture 80 corresponds in location to a recess82 in the top surface of shaft 14 as shown in FIG. 5. The recess 82bisects the wider portion 27 of slot 24 and has a rounded bottomsurface. Located within the recess 82 and extending from the aperture 80is a push button assembly 70 having a large diameter, external buttonportion 76 and a narrow diameter portion 74 that passes through theaperture 80. The narrow diameter portion 74 has a depression 75 with aflat bottom. The narrow diameter portion 74 terminates at its other endin a large diameter member 72 having a slightly smaller diameter thanthe diameter of the rounded recess 82. The large diameter member 72 hasa flattened top surface 73 so that it is flush with the top surface ofthe shaft 14 when the large diameter member 72 is inserted within therecess 82. The reverse end of the large diameter member 72 has a smalldepression 77 for receiving the end of a coil spring 84 a shown in FIG.4.

The large diameter member 72 is placed within the recess 82, so that thenarrow diameter portion 74 crosses the wider portion 27 of the slot 24at a right angle and extends through the rounded aperture 80 and theexternal button portion 76 is external to the shaft 14. The depression75 in the narrow diameter portion 74 is of a sufficient depth to permitthe stop pin 60 depending from the slide drive member 20 to easily passthrough the wider portion 27 of the slot 24 and over the depression 75unobstructed by the narrow diameter portion 74.

Within the recess 82 is a coil spring 84 having an end that fits withinthe small depression 77 of the large diameter member 72. The coil spring84 serves to bias the large diameter member 72 so that in its biasedposition, the large diameter member 72 blocks the wider portion 27 ofslot 24. The large diameter member 72 has a diameter that is sufficientto prevent the stop pin 60 from sliding over it. The external buttonportion 76 is at its greatest extension out of the rounded opening 80when the large diameter member 72 is in the biased position and blocksthe wider portion 27 of the slot 24. To unblock the wider portion 27 ofthe slot 24, the user simply presses the external button portion 76 ofthe button assembly 70 so that the coil spring 84 compresses and thelarge diameter member 72 moves further into the recess 82. When thelarge diameter member 72 is positioned as far into the recess 82 aspossible the depression 75 of the button assembly 70 is positioneddirectly beneath the stop pin 60 depending from the bottom surface ofthe slide drive member 20 so that the stop pin 60 can pass through thewider portion 27 of the slot 24 unobstructed.

It is appreciated that the rounded recess 82 may be placed at variouslocations along the shaft 14 so that the button assembly 70 containedtherein may also be positioned at various locations along the shaft 14beneath the slide drive member 20. The position of the stop pin 60depending from the slide drive member 20 may also be changed tocorrespond to the location of the button assembly 70 and theconfiguration of the slot 24 and the position of the wider portion 27may also be modified accordingly without departing from the scope of thepresent invention. For example, the rounded recess 82 may be positionedalong the shaft 14 so that it is located above the opening 15 and thethreaded aperture 17 of the body 12. In this position, the buttonassembly 70 in addition to controlling the displacement of the slidedrive member 20 along the shaft 14 could also serve as a hinge andattachment means for the forward handle 30 replacing the pivot pin 39.

As shown in FIG. 5, the shaft 14 has a pair of rails 62,63 extendingfrom either side of the shaft 14 which run parallel to the shaft 14. Therails 62,63 have a bottom flat surface 64 that is perpendicular to thesides of the shaft 14 as shown in FIG. 6. Near the distal end of theshaft 14 are forward notches 65,66 that provide a break in thecontinuity of the rails 62,63. Positioned proximal to the forwardnotches 65,66 are rear notches 69,71 which similarly provide a break inthe continuity of the rails 62,63.

The distal end 61 of the slide drive member 20 engages a cutting/storagemember 50 which is removably attached to both the shaft 14 and to theslide drive member 20. The cutting/storage member 50 has depending sides51 and 52 which are mirror images of each other. As shown in FIG. 4,near the distal end of the cutting/storage member 50 the depending sides51,52 each have forward rail-engaging members 53,54 respectively.Forward rail-engaging members 53,54 fit within the forward notches 65,66of shaft 14. Each of the forward rail-engaging members 53,54 has a topflat surface 68 that is perpendicular to the depending sides 51 and 52for engaging the bottom flat surface 64 of rails 62,63 as shown in. FIG.6. Once the forward rail-engaging members 53,54 are engaged to the rails62,63, the cutting/storage member 50 is prevented from sliding upward asit moves along the shaft 14.

Also located on each of the depending sides 51,52 of the cutting/storagemember 50 are rear rail-engaging members 56,57 which are sufficientlyspaced proximally from the forward rail-engaging members 53,54 so thatwhen the forward rail-engaging members 53,54 are placed over forwardnotches 65,66, the rear rail-engaging members 56,57 are directly overthe rear notches 69,71 in the shaft 14. The rear rail-engaging members56,57 are identical to the forward rail engaging members 53,54 andsimilarly each have a top flat surface 68 for engaging the bottom flatsurface 64 of rails 62,63.

Referring to FIGS. 2 and 4, the proximal end of the cutting/storagemember 50 has a male connection means 55 having grooves 58 on both sidesof a key portion 59. The male connection means 55 fits into a femaleconnection means 21 located at the distal end 61 of the slide drivemember 20. The female connection means 21 has rails 23 for engaging thegrooves 58 of the male connection means 55 and a notched area 78 forreceiving the key portion 59. The cutting/storage member 50 may beengaged to the slide drive member 20 by lowering the cutting/storagemember 50 toward the slide drive member 20 so that the male and femaleconnection means 55 and 21 slide into each other. To disengage thecutting/storage member 50 from the slide drive member 20, the cuttingstorage member 50 is simply lifted out. As an alternative, thecutting/storage member 50 may also be attached to the slide drive member20 in any number of conventional ways, such as by snap fit.

The cutting/storage member 50 is placed on the shaft 14 by aligning theforward rail-engaging members 53,54 with the forward notches 65,66 andby simultaneously aligning the rear rail-engaging members 56,57 with therear notches 69,71 so that the male connection means 55 slides into andengages the female connection means 21 of the slide drive member 20. Inorder to properly align the cutting/storage member 50 so that it mayengage the shaft 14, the slide drive member 20 must be positionedsufficiently proximal from the foot plate 16.

The range of proximal to distal movement of the slide drive member 20 iscontrolled by the large diameter member 72 of the button assembly 70. Inits biased position, the large diameter member 72 is positioned in thewide portion 27 of slot 24 so that the distal edge 79 of the largediameter member 72 blocks the stop pin 60 and thus the slide drivemember 20 from moving proximally along shaft 14. The appropriateposition of the slide drive member 20 for attaching the cutting/storagemember 50 to the shaft 14 may only be achieved by sliding the stop pin60 past the position of the distal edge 79 of the large diameter member72. In order to slide the stop pin 60 past the distal edge 79, thebutton assembly 70 must be manually depressed toward the shaft 14 sothat the large diameter member 72 is pushed into the recess 82 and ismoved out of the wide portion 27 of slot 24. As the forward handle 30 isbiased forward by the spring means 40 and 40 a, the slide drive member20 is moved proximately along the shaft 14 so that the stop pin 60 ispositioned within the depression 75 of the narrow diameter portion 74.With the stop pin 60 positioned within the depression 75, the largediameter member 72 is pushed back within the recess and the coil spring84 is compressed within the recess 82 of the shaft 14.

Once aligned with the forward and rear notches 65,66 and 69,71 andengaged to the slide drive member 20, the cutting/storage member 50 isin position to be pushed distally along shaft 14 by the slide drivemember 20 toward the foot plate 16. This is accomplished by squeezingthe forward handle 30 to move the slide drive member 20 and the stop pin60 distally so that the stop pin 60 is no longer within the depression75 of the narrow diameter portion 74, and the large diameter member 72is returned to its biased position by the coil spring 84. As thecutting/storage member 50 is engaged to the slide drive member 20, themovement of the cutting/storage member 50 is responsive to the movementof the slide drive member 20. As the cutting storage member 50 is moveddistally the front and rear rail-engaging members 53,54 and 56,57 engagethe rails 62,63.

Once the cutting/storage member 50 engages the rails 62,63 of the shaft14, it may not be lifted out and the cutting/storage member 50 is lockedto the shaft 14. The proximal movement of the slide drive member 20 isstopped by the large diameter member 72 in its biased position whichblocks the stop pin 60 from further proximal travel in the wider portion27 of the slot 24. To remove the cutting/storage member 50 from theshaft 14, the stop pin 60 must be again positioned by the user so thatit is within the depression 75 of the narrow diameter portion 74. Thus,the cutting/storage member 50 may be locked or unlocked to the shaft 14without the use of tools by simply pressing the button assembly 70.

The distal end of the cutting/storage member 50 opens into a storagechamber 88 which is bounded by upper and side walls 44 and 85 which aresharpened to form cutting edges 22 facing the foot plate 16. Thedepending sides 51,52 of cutting/storage member 50 are recessed from thefoot plate 16 for maximum bite since no cutting edge is required at thedepending sides 51,52. While the foot plate 16 may have a slight concavedepression, it is to be understood that it is preferable substantiallyflat, with or without a cutting edge.

The storage chamber 88 extends along the interior of the cutting/storagemember 50-at least partially toward its proximal end. The crosssectional area of the interior of the storage chamber 88 may be constantor preferably progressively increases from the distal end to theproximal end so that a number of successive bone fragments can moreeasily slide into the storage chamber 88 and stack up without jamming.

The rongeur 10 of the present invention is used in the conventionalmanner to bite bone or cartilage. The cut bone fragments are pushed bythe foot plate 16, one by one, into a stack within the storage chamber88 of the removable cutting/storage member 50 after being cut and arenot likely to fall back into the wound site because they are forced intothe storage chamber 88 with considerable force and are prevented fromjamming as the cross sectional area of the interior space of the storagechamber 88 increases from distal to proximal away from the cutting edge22. Thus, it is not necessary that the cut bone fragments be removedduring the surgical procedure, and bite after bite takes place, withoutthe need to remove the rongeur 10 from the wound.

In the preferred embodiment, the side walls 44 and 85 of thecutting/storage member 50 have narrow slits 86,87 partially along thelength of the cutting/storage member 50. Once the cutting/storage member50 is filled with cut pieces of bone, it is removed from the shaft 14and a stylet or similar instrument may be inserted through the slits86,87 on either of the side walls 44,85 to aid in the removal of the cutpieces from the storage chamber 88 containing the cut pieces.

Alternatively, the proximal end of the storage chamber 88 of thecutting/storage element 50 may also be open. During use, the distal end61 of the slide drive member 20 may be used to block the open proximalend of the storage chamber 88. Once the cutting/storage element 50 isremoved from the rongeur 10, the proximal end of the storage chamber 88is open and a stylet may be used to push the cut bone fragments storedwithin the storage chamber 88 so that the fragments exit from the distalend.

The use of a removable hollow cutting/storage member 50 permits a newsharp cutting edge to be provided for each operation as it may easily bereplaced. Both the storage chamber 88 and the cutting edge 22 could bemade of metal or any other suitable material such as ceramic for theedge or a plastic (e.g. polycarbonate) for the storage chamber 88.

In the preferred embodiment, the rongeur 10 has a body 12 that isapproximately 7¼ inches in length; a cutting/storage member 50 that isapproximately 3¼ inches in length and approximately ⅞ inches in heightand approximately ⅜ inches in width; a slide drive member 20 that isapproximately 3 9/16 inches in length and approximately ⅞ inches inheight and approximately ⅜ inches in width; a rear handle 13approximately 4⅞ inches in length and a front handle 30 approximately 4⅜inches in length having a extension member 33 that is approximately ⅞inches long; and a button assembly 70 having an overall length ofapproximately 7/16 inches.

In an alternative embodiment of the present invention, the rongeur 10includes a removable and disposable straw 90 as part of thecutting/storage member 50 as shown in FIG. 8. Straw 90 is a hollowmember in the shape of a cylinder or may have any other shape suitablefor use with rongeur 10. At the distal end of the straw 90 is a sharpcutting edge 92 for cutting bone or other similar tissue. The straw 90has a diameter that is sufficiently sized so that it may be insertedwithin the storage chamber 88 of the cutting/storage member 50. In thisembodiment, the distal end of the cutting/storage member 50 is truncatedso that the cutting edge 92 at the distal end of straw 90 extends fromthe chamber 88 and may be used to cut bone or cartilage against the footplate 16. In this embodiment, the cutting/storage member 50 is actuallya carrier member as the straw 90 does the actual cutting and storing ofthe bone. Prior to use, the straw 90 is inserted within the storagechamber 88 before the cutting/storage member 50 is placed on the shaft14. The hollow chamber 94 of the straw 90 functions to store the cutpieces of bone or cartilage. The stored cut pieces may be removed forfuture use in the same manner described above for the preferredembodiment.

Straw 90 has an open distal end and a proximal end that may be closedduring use of the rongeur. Additionally, straw 90 may have a crosssectional area that increases from its distal end to its proximal end.

In a further alternative embodiment, the straw 90 instead of beinginserted within the storage chamber 88 is affixed to the bottom of amodified cutting/storage base 96 as shown in FIGS. 9A and 9B. Thecutting/storage base 96 is identical in construction to thecutting/storage member 50 but does not have the storage chamber 88 andessentially acts as a housing for carrying the straw 90. The straw 90 isplaced in the bottom of the cutting/storage base 96 prior to placing thecutting/storage base 96 on the shaft 14. The straw 90 is held in placeand is prevented from rotating by pins 97,98 which complement thegrooves 101,102 in the straw 90 as shown in FIG. 9A, and prevent anymovement of the straw 90 within the cutting/storage base 96 during theoperation of the rongeur. Once the cutting/storage base 96 is removedfrom the shaft 14, the straw 90 is easily removable from thecutting/storage base 96.

The straw 90 is preferably made of metal or any other material which iscapable of being sharpened and maintaining a sharp cutting edge 92 formultiple bites by the rongeur 10. After the straw 90 is used and removedfrom the rongeur 10, the cut pieces contained therein are removed andmay be used for bone grafting purposes if desired. The relatively lowcost of the straw 90 allows the straw 90 to be truly disposable.

As a further alternative embodiment of the rongeur 10, the intersectionof the foot plate 16 and the shaft 14 may have a groove 29 as shown inFIGS. 10A and 10B to relieve crossed fields of stress. In thisembodiment, the distal end of the cutting/storage member 50 or of astraw 90 has an extension element 38 that complements the shape of thegroove 29 and fits within the groove 29. The extension element 38 may bemade of the same material as the cutting/storage member 50 or the straw90 or may be a flexible material such as plastic. As a result of theangled orientation of the foot plate 16, when the rongeur is fullyclosed, the cutting/storage member 50 or the straw 90 tends to be forcedup the inclination of the foot plate 16 which may result in damage tothe cutting edge 22 or 92. The combination of the groove 29 and theextension element 38 functions to prevent any further upward excursionof the cutting/storage member 50 or straw 90 and thus preventsadditional force from being applied to the foot plate 16 and preventsany possible damage to the cutting surfaces of the rongeur 10.

The operation of the rongeur 10 of the present invention is as follows:

The rongeur 10 is set in the “release position” by positioning the stoppin 60 within the depression 75 of the narrow diameter portion 74 of thebutton assembly 70. This is accomplished by manually pressing theexternal button portion 76 of the button assembly 70 so that the largediameter member 72 moves out of the wider portion 27 of the slot 24 tocompress the coil spring 84. The stop pin 60 may now freely pass by theposition of the distal edge 79 of the large diameter member 72 and tofit within the depression 75. As the spring means 40 and 40 a bias theforward handle 30 distally, the slide drive member 20 moves toward thefoot plate 16. With the stop pin 60 positioned within the depression 75,the coil spring 84 is kept compressed within the recess 82.

In the release position, the slide drive member 20 is positioned so thatthe cutting/storage member 50 may be easily placed on the shaft 14. Inthe release position, the forward rail-engaging members 53,54 arealigned with the forward notches 65,66 and the rear rail-engagingmembers 56,57 are aligned with the rear notches 69,71. Once aligned, thecutting/storage member 50 is positioned to easily engage the slide drivemember 20 so that the male and female connector means 55 and 21 mate andthe cutting/storage member 50 rests upon the shaft 14.

Once the cutting/storage member 50 is engaged to the slide drive member20, the forward handle 30 is squeezed by the user to advance the slidedrive member 20 so that the stop pin 60 exits from within the depression75 and the large diameter member 72 is returned by the coil spring 84 toits biased position to block the wider portion 27 of the slot 24. Withthe large diameter member 72 in this position, the stop pin 60 isstopped from any further proximal movement past the distal edge 79 ofthe large diameter member 72 thereby preventing any further proximalmovement of the slide drive member 20 past the large diameter member 72.With the slide drive member 20 in this position, the forward and rearrail engaging members 53,54 and 56,57 are engaged to the rails 62,63 andare no longer aligned with the forward and rear notches 65,66 and 69,71.Therefore, the cutting/storage member 50 is securely locked to the shaft14 and may not be removed from the shaft 14.

With the cutting/storage member 20 in the locked position on the shaft14, the rongeur 10 may be placed in the wound and used to take multiplebites or cuts of the selected tissue with the cut pieces being storedwithin the storage chamber 88 of the cutting/storage element 50. Oncethe desired number of bites has been attained or if the storage chamber88 becomes filled, the rongeur 10 is removed from the wound. Thecutting/storage member 50 is removed from the shaft 14 of the rongeur byreturning the rongeur to the release position by pressing the externalbutton portion 76 as described above, so that the forward and rearrail-engaging members 52,54 and 56,57 are once again aligned with theforward and rear notches 65,66 and 69,71 and no longer engage the rails62,63. The cutting/storage member 50 is then easily lifted up and awayfrom the shaft 14.

The cut pieces may be removed from the storage chamber 88 by inserting astylet in the slits 86,87 in the side walls 44,45 of the cutting/storagemember 50 and pushing the cut pieces out from the chamber. If analternative embodiment of the cutting/storage element 50 is used wherethe proximal end of the storage chamber 88 is closed only during use,the cut pieces may be pushed out of either end of the storage chamber88. Similarly, if a disposable straw 90 is used, the cut piecescontained within the straw 90 may be removed by using a stylet to thepush the cut pieces out of either the proximal or the distal end of thestraw 90 which are both open when not in use.

While the preferred embodiment of the present invention is a handpowered instrument, the use of alternative power sources such aselectricity, battery supply, pneumatic, or other power sources can beemployed.

In a powered rongeur, the finger grip of the rongeur can then be devotedto turning on and off the power supply source to drive the instrument.If gas or other fluid is used, a pressure relief valve is preferablyincorporated within the fluid line to establish a limit pressure, whichmay be set to the maximum desired biting force to be delivered.

Referring to FIG. 11, a powered rongeur 200 is shown. The grip 202 isadapted for receipt of the electronic circuitry 204 and the rechargeablebattery pack 206. A cover (not shown) holds the battery pack 206 withinthe grip 202.

Above the grip 202, is a housing 208 containing a wire coil 210 thatsurrounds a reciprocating rod 212. The rod 212 is connected at one end214 to the slide drive member 20. The rod 212 is spring biased by astrong spring 216 in the proximal direction. Whereby, upon activation ofthe trigger 218 which closes switch 220, the rod 212 is driven forwarddriving the slide drive member 20 and the cutting/storage member 50toward the foot plate 16. The speed of the rod 212 would result inadditional cutting force, due to the momentum of the slide drive member20. As a safety precaution, the momentum at which the rod 212 is drivenforward may be set to a desired rate so that excessive force is notexerted on the cutting edge 22 and the foot plate 16. For example, themomentum generated by the coil 210 and the rod 212 may be set at adesired rate for cutting bone or cartilage so that the rongeur 200 willnot bite a hard object, such as a metal pin, which requires a greatermomentum to cut and would damage the foot plate 16 and the cutting edge22.

Pulling of the trigger 218 closes the switch 220 to cause one closingand opening of the rongeur 200. For a second closing operation, thetrigger 218 must be released and then depressed again in order to closeswitch 220 once again.

The rear portion of the housing 208 can be opened for access to thecompartment by the removal of cap 222. Prior to sterilization, the cap222 and the coil 210 can be removed from the housing 208. The rongeur200 can be sterilized by heat upon removal of the coil 210 and thebattery pack 206. Alternatively, the device can be cold gas sterilizedor irradiated.

The rod 212 can be adjustable along the longitudinal axis, either bythreads or other means, so that it can be moved forward if necessary.Also, a safety mechanism for preventing activation of the switch 220,well known in electrically operated devices, can be included. This couldconsist of a mechanical interference between the trigger and the switchto prevent activation of the switch 220.

In use, the surgeon would insert the rongeur 200 around the lamina to becut and the trigger 218 would be pulled. The pulling of the triggerwould cause the slide drive member 20 and the cutting/storage member 50to be driven forward to close against the foot plate 16 cutting thebone, and then automatically returned to the original open position.Releasing the trigger 214 would permit the cutting/storage element 50 toreturn to its open position. The surgeon would then move the rongeur200, without removing the rongeur 200 from the wound, to a new area forbiting the bone, again activating the trigger and causing the rongeur toclose. The device could be programmed to close at a predetermined rate,so that it would automatically open and close. After completion of thecutting procedure the rongeur 200 would be removed and thecutting/storage member 50 removed and replaced in the same mannerdescribed above for the manual rongeur 10.

While the present invention has been described in association with thepreferred embodiment, it is recognized that other variations of thepresent invention may be made without departing from the scope of thepresent invention.

1. A method for cutting bone or cartilage, the method comprising thesteps of: providing a rongeur having a shaft with a mid-longitudinalaxis, a foot plate extending from the shaft, and a storage member inmoveable relationship to the shaft, the storage member having a cuttingedge and a storage area adapted to store multiple cuts of bone orcartilage; positioning the rongeur at a site where the bone or cartilageis to be cut; cutting bone or cartilage with the rongeur to producemultiple cut pieces of bone or cartilage; storing the cut pieces of boneor cartilage in the storage area of the storage member; and moving thestorage member away from the mid-longitudinal axis of the shaft in adirection generally radial to the mid-longitudinal axis while the cutpieces of bone or cartilage are still in the storage area.
 2. The methodof claim 1, further comprising the steps of replacing the storage memberwith a second storage member and engaging the second storage member withthe shaft.
 3. The method of claim 2, further comprising the step oflocking the second storage member to the shaft.
 4. The method of claim1, further comprising the step of disposing the storage member.
 5. Themethod of claim 1, wherein the storage area increases in cross sectionalarea from one end of the storage member to another end of the storagemember.
 6. The method of claim 1, wherein the step of cutting includesreciprocating the storage member relative to the shaft to cut the boneor cartilage.
 7. The method of claim 1, wherein the step of cuttingincludes manually cutting the bone or cartilage.
 8. The method of claim1, wherein the step of cutting includes electrically operating therongeur to cut the bone or cartilage.
 9. The method of claim 1, whereinthe storage member is insertable into a carrier member, the step ofmoving including moving the carrier member away from themid-longitudinal axis of the shaft in a direction generally radial tothe mid-longitudinal axis.
 10. The method of claim 9, further comprisingthe step of removing the storage member from the carrier member.
 11. Themethod of claim 10, further comprising the steps of inserting a secondstorage member into the carrier member and attaching the carrier memberto a portion of the shaft of the rongeur.
 12. The method of claim 1,further comprising the step of removing the cut pieces of bone orcartilage from the storage area of the storage member after removal ofthe storage member from the shaft.
 13. The method of claim 12, furthercomprising the step of utilizing the cut pieces of bone or cartilageremoved from the storage member in another medical procedure.
 14. Themethod of claim 1, wherein the step of cutting includes producingmultiple cut pieces of bone or cartilage without removing the rongeurfrom the patient.
 15. The method of claim 1, further comprising thesteps of moving the storage member toward the shaft from a directionabove the shaft, and engaging the storage member to the shaft.
 16. Themethod of claim 15, wherein the step of engaging includes snap fittingthe storage member onto the shaft.
 17. The method of claim 1, furthercomprising the step of replacing the cutting edge with a differentcutting edge.
 18. The method of claim 1, wherein the step of storing isperformed without ejecting the pieces of bone or cartilage stored withinthe storage member while the rongeur is being used to take additionalcuts of bone or cartilage.
 19. The method of claim 1, further comprisingthe step of replacing the foot plate with a second foot plate.
 20. Themethod of claim 1, further comprising the step of releasably locking thestorage member to the rongeur.